Method of preparing acetaldehyde.



paring -acetaldehyde g According to "place. lf

COMPANY, 0F NEW YORK, TN'. Y., A CQEPOTON 0F VG.

y Speceatton of Letters Patent.

1:1 se nennst.

Patentedhlov.. 2d, that?.

application and apra as', 1ere. serial no; narra` To all whom it may concern.'

Be it known lthat I, HAROLD Hmnnn'r, a-

subject of the King of Great Britain, residingat Pittsburgh, in the county of Allegheny and State or Pennsylvania., have invented certain new and use ul Improvements innMethods of Preparing Acetaldeh'yde, of which the following is a speciii'catioi'i. This invention relates to methods of pretrom acetylene. lt is well known thatv acetylenemay becaused to unite with the elements otwater, yielding acetaldehyde,by bringing it into contact with a suitable compoundv of mercury in presence of solutions of sulfuric or equivalent strong acid. rEhe present invention is an improvement upon processes of this general' character, and has for its obj ect the provision of 'an economical and highly ecient mode of operattheinvention acetylene is led into an acid bath of the general character above mentioned, in material excess of the amount which can be absorbed. in the rst reaction. The bath is referably maintained at a temperature o 0-80 C., whereby the bulk ofthe acetaldehyde formed is continuously distilled o', mixed with the excess of acetylene. These mixed gases are conveyed directly to a secondacidbath, preferably having the same characteristics as the first, where a further reaction takes the' 'further reaction will contain a lproportionately lsmaller amount of acetylene, `inay. be conveyed to a third bath, and so on to any desired number of series-,connected condensing system, from which anyresidualacetylene ma bereturned to the tirst element of the a sorption system, together with suiiicient added acetylene to restablish the A desired excess. The rate or supply of acetylene to the system will depend upon several factors, including the number or vessels in series, the volume oit the acid baths, and their conversion eiiciency. Usually it is preferied to supply `acetyleneat such rate that some per cent., more orless, otthe Without restricting the desired the ,coingled gases'A 'from this second-bath, which by reason of gas entering the first absorption vessel will pass vtherefrom to the next in series.

T he accompanying drawing illustrates in a dlagrammatic manner one type of system suitable for the practice of this invention, the ligure being a central longitudinal sectional view of a series of four reaction vessels. Each of these vessels, designated by numeral l, 2, 3 and 4, is shown as provided with an agitator 5, and with a perforated coil 6 by which the iniiowing gases are distributed beneath the liquid in the acid-bath 7. rThe mixed gases arising from each vessel pass directly through sel next in series, as described above, and from 4the nal vessel 4c the gases are conveyed to any suitable condenser 8. |lhe condensed acetaldehyde is withdrawn from the collectin vessel 9 through the tap 10, and any resi ual acetylene is returned to the system through conduit 11, by means of a pump l2 or equivalent device. Additional acetylene mayy flow into the system through the valved conduit 13.

. As I have stated above the conversion of acetylene into acetaldehyde proceeds with a high degree of efliciency when a plurality of series connected reaction vessels are em ployed, as distinguished from carrying out the reaction in a single body of liquid.

i' invention by reference to any theoretical considerations, it may be pointed out as a"'possible explanation of the above observedact, that the presence of acetaldehyde apparently increases to a material degree the-solubility of acetylene, and its reactivity, in the acid solutions used. Hence one tendency of the series arrangement of the reaction vessels is to equalize the conditions throughout the system as follows: The ressure of acetylene, and therefore its solubility in the liquid in accordance with the bath in the vesthe law of partial pressure, islo course at a maximum inthe first reaction vessel in series, and decreasessthronghout the system. Un the other handwthie concentration of the acetaldehyde is at a-r'fn'nimum in the first re action vessel and tends to increase throughout the series. The combined tendency oii these two factors may be to equalize the reacting conditions throughout the system. Whatever may be the explanation of the results, the observed fact is that under such con ditions as have been described above the reaction proceeds with rapidity and smoothness,

Mbit

lill@ and With but little tendency to the formation of leyproducts of reaction.

Whlle my lnvention is not restricted to any particular constitution of bath for-carrying out the reaction, satisfactory results are obtained using such acidvbaths as are disclosed in the copending applications of Hibbert and Morton, Serial N os. 59,836, and 59,837, filed November 5, 1915. A

vI claim-:

1. A method of preparing acetaldehyde from acetylene, which consists in effecting a combination of acetylene with the elements of Water in a suitable acid bath, and conyeying vapors of acetaldehyde arising-from said `i bath, commingled with acetylene, to one or more baths connected in series with and similar 1n composition to the rst.

` v narrato 2. A method of preparing acetaldehyde from acetylene, which consists in effecting a combination of acetylene with the elements of Water in an acid nbath containing a mercui-y compound and maintained at a suliiclent temperature for the continuous distil-y HAROLD HIBBERT.

Witnesses as; 1 

